ATSB chief commissioner Greg Hood says the investigation has “begun in earnest” to try and piece together what brought down charter company Rossair’s Cessa Conquest near Renmark on Tuesday afternoon.

Killed in the crash were Rossair’s chief pilot Martin Scott, 48, fellow pilot Paul Daw, 65, and Civil Aviation Safety Authority inspector Stephen Guerin, 56.

Hood says the crash is unusual because accidents of its kind are uncommon and each of the men on board were experienced pilots.

“In my experience it’s an unusual accident and it’s not something that you can put your finger on and say that’s likely to be the cause straight away,” he told reporters in Renmark today.

“This will be a complex investigation. We don’t see these types of accidents very often in Australia.”

Hood said the plane had been in the air for about 60 to 90 seconds before it plunged to the ground and the concentration of the crash site meant it could have fallen steeply.

“It’s about 40 metres all in all, and so that tells us that potentially the aircraft has gone in at a reasonably steep rate of descent,” he said.

The ATSB plans to issue a preliminary report within 30 days of its investigation and a final report within 12 months.

Rossair chief executive Warren Puvanendran says the company has grounded its operations and will co-operate fully with investigations.

He says the company won’t speculate on a possible cause of the crash but at this stage doesn’t know what went wrong.

Puvanendran says Rossair will take advice from CASA on when it can resume operations.

“My priority at the moment is not to delve too deeply into the incident but to look after the families of the deceased and also our current employees,” he said.

– AAP